I'm starting a 6x6 roto league and I've stuggled a bit on determining what the 6th pitcher category should be. I eventually settled on total bases allowed, but now I'm a little concerned that owners could abuse this by loading up on relievers. They would be able to dominate TBA simply through lack of innings, and they would be very competitve in SV, ERA and WHIP. Would their inability to keep up in W's in K's (remember, this is a roto league) be enough to offset that? I'm curious as to what you guys think.

Note: The reason I went with TBA is I feel like it is the only stat Yahoo offers that isn't redundant with the basic five. Yahoo doesn't have an option for SLG against, or even Batting Average against.